This invention relates to a web or continuous strip of clear laminate that is formed to the exact size of a substrate on which the laminate is to be used, and which web has reduced strength lines transversely of the web at the exact or very slightly shorter length dimension of the substrate on which it is to be applied.
Plastic cards used for identification cards are personalized with text and images using resin and dye diffusion thermal transfer (D2T2) ribbons. Unless protected with another resin layer or film laminate, the dye (and thus the image printed) can rapidly degrade from abrasion, chemical attack from plasticizers such as those found in vinyl wallet windows, and from ultraviolet radiation (UV), for example.
Thermal transfer resin layers typically used in the plastic card industry consist of thin acrylic coatings. These provide some protection to the card surface and printed information, however, but longer term durability is a problem, as none of these thermal transfer materials is durable enough to satisfy customers. A second problem is that dye migration may still occur since the thermal film is made of porous material which cannot protect the dye from plasticizers and the like.
A third problem is in the application of the material as it tends not to stay on the card when laminated, especially along the edges of the card, and it flakes when laminated causing debris problems in the printer.
In order to improve on these thin thermal transfer layers, thicker laminates consisting of polyester film (PET) coated with a thermal transfer adhesive have been developed. In one type of laminate system, these laminate xe2x80x9cchipsxe2x80x9d or xe2x80x9cpatchesxe2x80x9d are placed adhesive-side up on a pressure sensitive adhesive (PSA) coated carrier film of PET. During lamination to the card in the printer, the patch is transferred to the surface of the card. These types of patches typically cover only about 90% of the card surface. Dye migration, UV fading and abrasion can still occur on the edges of the card. Laminate patches can also be cut from a supply roll of PET film laminate and applied to cards in the printer, however, these rectangular patches also only cover about 90% of the card.
The use of individual laminate patches carried on a backing film for lamination onto a substrate is shown in U.S. Pat. Nos. 5,807,461 and 4,617,080. Also, the application of an overlay film on a printed paper is disclosed in U.S. Pat. Nos. 4,522,881; 4,599,259; and 4,977,136. The use of a continuous web with weakened transverse lines for separation sections is not shown.
The present invention relates to providing a transparent laminate material and scoring transverse lines on the web to form individual sections of a size that fits edge to edge on the length and width of a substrate. The transverse lines are weakened to have a tear strength in the range of two pounds tensile pull for standard two inch widths. This strength is obtainable for commonly used laminate thickness of 1.0 to 1.5 mils. The tear strength is selected to permit separating out the individual sections for laminating them to a substrate, a range of tear strength from about 0.75 pounds per inch of width to about 1.25 pounds per inch with the three pound maximum will work. The sizes can be controlled to within a few thousandths of an inch so the laminate sections which are nominally full size or very close to full size of the substrate, can be laminated on discrete or individual substrates without waste and using automated equipment. Virtually the entire card surface will be covered. Present automated equipment requires no more than 3 lb. tensile pull for severing individual sections.
The full size lamination section or patch protects the substrate, such as an identification card so the full surface of the substrate can be used for printing or otherwise recording information.